An experimental design for studying how driver characteristics influence headway control

The sample of drivers, representing a random sample of the population of licensed drivers in southeastern Michigan, was selected according to a design that stratified the population by age and prior use of conventional cruise control. An essential element of the design was that each driver's operation with adaptive cruise control (ACC) is compared with the same individual's driving in the "manual" mode of vehicle operation. The experimental design was based, in part, on findings from previous research projects. Specifically, the independent variables of participant age and conventional cruise control usage were previously found to influence both objective and subjective dependent measures. The paper delineates the experimental design and outlines its execution.